LFCS Storage Management Practice Question
Exhibit
Refer to the exhibit. # df -h /data Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_data-lv_data 100G 50G 50G 50% /data # lvextend -L +10G /dev/mapper/vg_data-lv_data Size of logical volume vg_data/lv_data changed from 100.00 GiB to 110.00 GiB. Logical volume vg_data/lv_data successfully resized. # df -h /data Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_data-lv_data 100G 50G 50G 50% /data
After extending the logical volume, the df output still shows 100G. What is the most likely reason?
⚠ Common exam trap
Candidates often assume extending the logical volume automatically resizes the filesystem, but the LFCS exam tests the explicit two-step process: LV extension followed by filesystem resize.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The filesystem on the logical volume has not been resized.
`lvextend` only increases the size of the logical volume at the block device level. The filesystem (e.g., ext4, XFS) still sees the original size until it is explicitly resized with a command like `resize2fs` (for ext4) or `xfs_growfs` (for XFS). The `df` command reports filesystem usage, not the underlying block device size, so the filesystem must be grown to match the LV.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The filesystem on the logical volume has not been resized.
Why this is correct
Extending the logical volume only enlarges the block device; the filesystem on top retains its original size until explicitly grown. Since df reports filesystem capacity, not volume size, it still shows 100G. Resizing the filesystem (for example with resize2fs or xfs_growfs) is required to reflect the added space.
- ✗
lvresize must be used instead of lvextend.
Why it's wrong here
lvextend already enlarges the logical volume; lvresize performs the same resize operation and would not grow the filesystem either. lvresize is tempting because it can both extend and reduce volumes, making it the correct tool when shrinking an LV, which lvextend cannot do.
- ✗
The kernel has not detected the new size; reboot required.
Why it's wrong here
The kernel updates the block device size immediately on lvextend; no reboot is needed. The filesystem, not the kernel, still reports the old size until grown. Rebooting is tempting because it forces re-detection of hardware changes, which is the correct fix for added disks or resized partitions on some systems.
- ✗
The mount point must be remounted with the 'remount' option.
Why it's wrong here
Remounting refreshes mount options, not the block device size; the filesystem itself must be grown with resize2fs or xfs_growfs after lvextend. Remount is tempting because it applies changed mount flags live, which is the correct action when altering options like noatime or ro, not capacity.
Go deeper
Related to this question
About these practice questions
Courseiva writes every LFCS question from scratch — 406 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LFCS practice question is part of Courseiva's free Linux Foundation certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LFCS exam.